"You are all disgusting child molesterors, how do you live with yourselves?" another critic wrote on the show's Facebook page. "What, you didnt go to the prom so now you gotta dress your 5 yr old up like a hooker to fill that achey breakey heart of yours?"

Levin noted that the girls' dolled-up looks could push some adults who have trouble keeping boundaries with underage girls even further.

"This could blur the boundaries for people who are having trouble controlling their pedophilia predisposition," said Levin.

While a 4-year-old wearing fake breasts is an extreme version of this type of objectification, this sexiness begins to normalize the expectation of little girls' appearances, Levin said.

In response to the "increasing problem" of the sexualization of girls in the media, the American Psychological Association created a task force to research and respond to the problem.

"We don't want kids to grow up too fast," Shari Miles-Cohen, senior director of women's programs for the American Psychological Association, told ABCNews.com in August. "We want them to be able to develop physically, emotionally, psychologically and socially at appropriate rates for their age."

Testing out adult behaviors as a child may have lifelong consequences, said Dr. Ari Brown, a Texas pediatrician and author of "Toddler 411."

While Brown said one cannot assume that all young girls who dress inappropriately turn out to have early sexual experiences or other risky behaviors, "I do wonder what type of limit setting and discipline occurs in their household," she said.